On 22/04/2025 8:58 pm, Stefano Stabellini wrote: > On Tue, 22 Apr 2025, Andrew Cooper wrote: >> On 22/04/2025 8:46 pm, Stefano Stabellini wrote: >>> On Tue, 22 Apr 2025, Andrew Cooper wrote: >>>> Compilers estimate the size of an asm() block for inlining purposes. >>>> >>>> Constructs such as ALTERNATIVE appear large due to the metadata, depsite >>>> often >>>> only being a handful of instructions. asm inline() overrides the >>>> estimation >>>> to identify the block as being small. >>>> >>>> This has a substantial impact on inlining decisions, expected to be for the >>>> better given that the compiler has a more accurate picture to work with. >>>> >>>> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> >>> Hi Andrew, >>> >>> If we are going to use asm_inline, please add a note to >>> docs/misra/C-language-toolchain.rst where we keep record of all the >>> language extensions we use. >> It's just asm(), and that's already discussed. >> >> I'm not sure what else you think is warranted. > > If it is just asm() then there is nothing to do. We only need to > document extensions to the language, nothing else. Many of them are > already documented under docs/misra/C-language-toolchain.rst (see for > instance asm and __asm__). > > I see the critical part of the patch for this question is: > >> +#if CONFIG_CC_HAS_ASM_INLINE >> +# define asm_inline asm __inline >> +#else >> +# define asm_inline asm >> +#endif > it looks like __inline is an extension ?
That's just inline. (It's an alternative spelling, and we discuss those too.) The reason it's not plain "asm inline" is because of the (deviated) "#define inline inline __init", where an eventual "asm inline __init (..." is a syntax error. ~Andrew
